package com.wlyuan.gateway.controller;

import lombok.AllArgsConstructor;
import org.springframework.cloud.gateway.config.GatewayProperties;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.support.NameUtils;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Component;
import springfox.documentation.swagger.web.SwaggerResource;
import springfox.documentation.swagger.web.SwaggerResourcesProvider;

import java.util.ArrayList;
import java.util.List;

/**
 * @author c3
 */
@Component
@Primary
@AllArgsConstructor
public class ResourcesProvider implements SwaggerResourcesProvider {
    private static final String API_URI = "/v2/api-docs";
    private final RouteLocator routeLocator;
    private final GatewayProperties gatewayProperties;


    private static class GatewayResources extends ArrayList<SwaggerResource> {
        private SwaggerResource createResource(String name, String location) {
            SwaggerResource swaggerResource = new SwaggerResource();
            swaggerResource.setName(name);
            swaggerResource.setLocation(location);
            swaggerResource.setSwaggerVersion("2.0");
            return swaggerResource;
        }

        public void add(RouteDefinition routeDefinition, PredicateDefinition predicateDefinition) {
            String location = predicateDefinition.getArgs()
                    .get(NameUtils.GENERATED_NAME_PREFIX + "0")
                    .replace("/**", API_URI);
            add(createResource(routeDefinition.getId(), location));
        }
    }

    private void handleRoute(GatewayResources resources, RouteDefinition route) {
        route.getPredicates()
                .stream()
                .filter(predicateDefinition -> ("Path").equalsIgnoreCase(predicateDefinition.getName()))
                .forEach(predicateDefinition -> resources.add(route, predicateDefinition));
    }

    @Override
    public List<SwaggerResource> get() {
        GatewayResources resources = new GatewayResources();
        List<String> routes = new ArrayList<>();
        //取出gateway的route
        routeLocator.getRoutes().subscribe(route -> routes.add(route.getId()));
        //结合配置的route-路径(Path)，和route过滤，只获取有效的route节点
        gatewayProperties.getRoutes()
                .stream()
                .filter(routeDefinition -> routes.contains(routeDefinition.getId()))
                .forEach(routeDefinition -> handleRoute(resources, routeDefinition));
        return resources;
    }

}